ASSESSMENT OF THE DYNAMIC STRUCTURAL RESPONSE OF BUILDINGS BASED ON EXPERIMENTAL MONITORING AND FEM SIMULATIONS

Resumo

Numerical analyses based on the Finite Element Method (FEM) simulations are present in
everyday routine of many academic centres and structural design offices around the world. However,
one of the problems to be solved is the FEM reliability, in order to represent the actual response of the
analysed structural model. Currently, it is possible to use the results of dynamic experimental monitoring
to verify and adjust the numerical model and consequently improve accuracy of the results. The dynamic
experimental monitoring allows the extraction of modal parameters (natural frequencies, vibration
modes and damping coefficients). These parameters are relevant for a correct characterization of the
investigated model and are calculated based on the experimental signals of accelerations, velocities and
displacements. This way, in this work, the modal parameters, related to a real 5-story steel building
constructed in laboratory are determined, based on dynamic experimental monitoring. In sequence,
aiming to validate the motion equations of the structural system, both numerical and experimental
dynamic responses of the physical model were correlated. The results are presented in terms of modal
parameters, frequency response functions (FRFs) and time history. These modal parameters were used
to calibrate the steel building FEM. The proposed computational model, developed for the investigated
steel building dynamic analysis, adopted the usual mesh refinement techniques present in FEM
simulations implemented in the ANSYS program. In this numerical model, the steel columns were
represented by three-dimensional beam elements, where flexural and torsional effects are considered.
The slabs were represented by shell elements. After that, a forced vibration analysis was carried out and
the dynamic response of the building, when subjected to impact loads, was compared with the actual
structural response of the steel building model. The conclusions emphasize the relevance of the dynamic
experimental monitoring to characterize and adjust the developed FEM of the investigated building. The
good agreement between the numerical and experimental results can corroborate the adequate use of the
developed numerical model.